查看更多>>摘要：Doubled haploid(DH)technology and synthetic apomixis approaches can considerably shorten breeding cycles and enhance breeding efficiency.Compared with traditional breeding methods,DH technology of-fers the advantage of rapidly generating inbred lines,while synthetic apomixis can effectively fix hybrid vigor.In this review,we focus on(ⅰ)recent advances in identifying and characterizing genes responsible for haploid induction(HI),(ⅱ)the molecular mechanisms of HI,(ⅲ)spontaneous haploid genome doubling,and(iv)crop synthetic apomixis.We also discuss the challenges and potential solutions for future crop breeding programs utilizing DH technology and synthetic apomixis.Finally,we provide our perspectives about how to integrate DH and synthetic apomixis for precision breeding and de novo domestication.
查看更多>>摘要：Maize develops separate ear and tassel inflorescences with initially similar morphology but ultimately different architecture and sexuality.The detailed regulatory mechanisms underlying these changes still remain largely unclear.In this study,through analyzing the time-course meristem transcriptomes and floret single-cell transcriptomes of ear and tassel,we revealed the regulatory dynamics and pathways underlying inflorescence development and sex differentiation.We identified 16 diverse gene clusters with differential spatiotemporal expression patterns and revealed biased regulation of redox,programmed cell death,and hormone signals during meristem differentiation between ear and tassel.Notably,based on their dynamic expression patterns,we revealed the roles of two RNA-binding proteins in regulating inflorescence meri-stem activity and axillary meristem formation.Moreover,using the transcriptional profiles of 53 910 single cells,we uncovered the cellular heterogeneity between ear and tassel florets.We found that multiple sig-nals associated with either enhanced cell death or reduced growth are responsible for tassel pistil suppres-sion,while part of the gibberellic acid signal may act non-cell-autonomously to regulate ear stamen arrest during sex differentiation.We further showed that the pistil-protection gene SILKLESS 1(SK1)functions antagonistically to the known pistil-suppression genes through regulating common molecular pathways,and constructed a regulatory network for pistil-fate determination.Collectively,our study provides a deep understanding of the regulatory mechanisms underlying inflorescence development and sex differen-tiation in maize,laying the foundation for identifying new regulators and pathways for maize hybrid breeding and improvement.
查看更多>>摘要：Wheat is a staple food for more than 35％of the world's population,with wheat flour used to make hundreds of baked goods.Superior end-use quality is a major breeding target;however,improving it is especially time-consuming and expensive.Furthermore,genes encoding seed-storage proteins(SSPs)form multi-gene families and are repetitive,with gaps commonplace in several genome assemblies.To overcome these barriers and efficiently identify superior wheat SSP alleles,we developed"PanSK"(Pan-SSP k-mer)for genotype-to-phenotype prediction based on an SSP-based pangenome resource.PanSK uses 29-mer sequences that represent each SSP gene at the pangenomic level to reveal untapped diversity across landraces and modern cultivars.Genome-wide association studies with k-mers identified 23 SSP genes associated with end-use quality that represent novel targets for improvement.We evaluated the ef-fect of rye secalin genes on end-use quality and found that removal of ω-secalins from 1BL/1RS wheat translocation lines is associated with enhanced end-use quality.Finally,using machine-learning-based prediction inspired by PanSK,we predicted the quality phenotypes with high accuracy from genotypes alone.This study provides an effective approach for genome design based on SSP genes,enabling the breeding of wheat varieties with superior processing capabilities and improved end-use quality.
查看更多>>摘要：Karrikins and strigolactones govern plant development and environmental responses through closely related signaling pathways.The transcriptional repressor proteins SUPPRESSOR OF MAX2 1(SMAX1),SMAX1-like2(SMXL2),and D53-like SMXLs mediate karrikin and strigolactone signaling by directly binding downstream genes or by inhibiting the activities of transcription factors.In this study,we characterized the non-transcriptional regulatory activities of SMXL proteins in Arabidopsis.We discovered that SMAX1 and SMXL2 with mutations in their ethylene-response factor-associated amphiphilic repression(EAR)motif had undetectable or weak transcriptional repression activities but still partially rescued the hypocotyl elonga-tion defects and fully reversed the cotyledon epinasty defects of the smax1 smxl2 mutant.SMAX1 and SMXL2 directly interact with PHYTOCHROME INTERACTION FACTOR 4(PIF4)and PIF5 to enhance their protein stability by interacting with phytochrome B(phyB)and suppressing the association of phyB with PIF4 and PIF5.The karrikin-responsive genes were then identified by treatment with GR24ent-5DS,a GR24 analog showing karrikin activity.Interestingly,INDOLE-3-ACETIC ACID INDUCIBLE 29(IAA29)expression was repressed by GR24ent-5DS treatment in a PIF4-and PIF5-dependent and EAR-independent manner,whereas KARRIKIN UPREGULATED F-BOX 1(KUF1)expression was induced in a PIF4-and PIF5-independent and EAR-dependent manner.Furthermore,the non-transcriptional regulatory activity of SMAX1,which is independent of the EAR motif,had a global effect on gene expression.Taken together,these results indicate that non-transcriptional regulatory activities of SMAX1 and SMXL2 mediate karrikin-regulated seedling response to red light.
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